Collapsible container with corrugations to facilitate the collapse of its walls



Apnl 2, 1963 w. K. GASH 3,083,877

COLLAPSIBLE CONTAINER WITH CORRUGATIONS T0 FACILITATE THE COLLAPSE OF ITS WALLS Filed 001;. 25, 1960 rates This invention relates to containers and especially, but not exclusively, to containers made of flexible synthetic plastic materials,

Containers are at the present time molded in synthetic plastic materials for a large variety of purposes and one of these purposes is for holding battery acid in a quantity suitable for filling into a battery when the battery is required for use. Such plastic containers are made in large quantities and as theyv are required to hold a substantial volume of liquid a problem has hitherto existed in the large space occupied by these containers when being transported empty from the factory of manufacture to the factory in which the acid is filled into them. The relatively large volume occupied by the bottles when empty has increased transpor costs and has given rise to difficulties in handling which would be greatly reduced if the volume of such containers could be reduced without affecting the carrying capacity of the containers.

It is accordingly an object of this invention to provide containers in which the disadvantages referred to above are substantially overcome.

Other objects and advantages of the invention will be apparent from the ensuing description.

According to this invention we provide a collapsible container having at least one, and preferably several, corrugations molded into, and extending around, the container wall, the container wall being formed of fiexi ble material whereby, by virtue of the said corrugation or corrugations, the container can be collapsed or reduced in volume for packing or transport purposes when empty, and expanded from its collapsed form to its normal size and shape when required for the purpose of holding liquids or other material. Preferably, the container wall is formed so that when the container is in its collapsed state and a liquid is poured into the container while the container is suspended from its upper end and unsupported at its lower end, the weight of the liquid in the container will be suflicient to cause the container to expand downwardly whereby it tends to return to its normal size and shape.

In order that the invention may be more fully understood, the preferred embodiment thereof will now be described with reference to the accompanying drawings, of which:

FIGURE 1 is a perspective View of an acid container in accordance with the invention,

FIGURE 2 is a section along the plane 2-2 of FIG- URE 1, and

FIGURE 3 is a sectional elevation of the container in a collapsed state.

The container 1 is molded from polyethylene or other suitable acid-resistant plastic material. The container is rectangular in plan and provided with rounded corners. A series of corrugations 2 extend horizontally around the container wall so that the container is concertina-like in appearance. A container of this type may conveniently be made to hold either one gallon or three-quarters of a gallon and in either case the corrugations may comprise three ridges 3 separated from the top and bottom portions of the container by four valleys 4, the pitch of the corrugations being 1% inches and the upper portion 5 and lower portion 6 of each corrugation 2 being disposed at atent O angles of about 45 to the horizontal when the container is in an upright position and in its normal (or expanded) condition as shown in FIGURES l and 2, The valleys 4 and the ridges 3 are rounded at their inner and outer extremities 7 and 8 respectively so as to avoid the formation of undesirably narrow fold lines when the container is collapsed as shown in FIGURE 3. The above quoted measurements are of course only stated by way of example and are not in any way to be regarded as limiting the invention thereto.

A cylindrical neck 9 is molded integrally on the top face 10 of the container and the outside surface of the neck 9 is provided with a thread 11 so that an internally threaded closure cap can be secured thereon. To facilitate packing of the containers as hereinafter explained, the neck 9 is located nearer to the end 12 of the container than to the end 13. The top and bottom portions of the container 1 are also provided with short corrugations l-i extending around each corner in order to facilitate deformation of the container when it is collapsed.

Any convenient form of closure may be used to seal the container, but in one form, the closure comprises a cap 16 provided with an opening in its upper wall, and a. length of flexible tubing 17 closed at one end and molded integrally with a plastic washer 18 which is of the same diameter as the top of the neck of the container and is located at the other end of the tubing.

After being molded by any suitable known method, the containers are collapsed by the application of downward pressure thereto so that the volume may be reduced to a third or less. They are then packed in this condition for transport to the factory at which they are to be filled with battery acid. To carry out this operation, the containers are removed from their packing and placed on a jig which is shaped to support the container by hearing against the upper portion 5 and the lower portion 6 of the topmost corrugation 2. It is not necessary to expand the container fully from its folded form prior to the acid being poured in, as the weight of the liquid poured into the container will itself cause the expansion. Desirably, the containers are arranged so that they will come into contact with a supporting bench or the like when they are about half full in order to prevent the containers from becoming overstretched. When a container has thus bee filled with acid, the washer is placed on the top of the neck so that the closed end of the tube projects upwardly from the neck, The container is then sealed by moving the closure cap downwardly on to the neck to that the projecting tube passes through the central opening in the cap and then tightening the cap on the threaded portion of the neck so that the plastic washer is pressed downwardly against the upper edge of the neck. The filled container may then be packed in a rectangular carton adjacent to the end of an unfilled battery and the projecting tube is then folded downwardly by the closing and sealing of the carton closure flaps.

-When it is desired to pour the acid from the container into a battery, the closed end of the tube is severed by means of a knife or the like so that the tube becomes open and the acid may then be poured from the container into the battery through the projecting spout.

The thickness of the container walls is such in relation to the nature of the material and the dimensions of the container that, when the container is in its normal (as molded) shape, it will not tend to collapse or distort to any substantial extent and may therefore be handled in the same way as a relatively rigid non-collapsible molded bottle or container. It will thus be apparent that containers according to the invention combine the features of both collapsible non-self-supporting hollow devices (such as a thin walled rubber bellows) and a normal noncollapsible molded bottle or the like.

In the case of rectangular blow-molded polyethylene containers of sizes suitable for holding between 0.6 gallon and 1.2 gallons, the minimum wall thickness (which occurs at the corners) should not be less than inch, while the average thickness around the fold lines of the container is conveniently about inch.

In a modification, a pair of upwardly projecting apertured lugs 15 are molded on the upper surface of the container in such manner that the container can be supported, while being filled, on horizontal rods passed through the apertures in the lugs. These lugs 15 may be arranged on opposite sides of the neck 9 and equidistant from the ends of the container.

The invention has been particularly described with reference to its embodiment in the form of a container suitable for holding battery acid, but it is obvious that the invention may be applied to containers suitable for other purposes and the above description is to be understood accordingly, However, it will be appreciated that the form of container described is particularly convenient for use as a container for battery acid, as not only does it enable transport and packaging costs for the empty containers'to be reduced, but the shape of the container, that is rectangular in plan, has the added advantage that the containers occupy less space, when filled, than round containers of similar capacity, Moreover the shape of the container is such that it may conveniently be packed in a carton with a battery case as the latter is itself normally rectangular in plan.

When the containers are being transported in their empty condition, the arrangement of the neck in the offcentre position enables the containers to be placed in reversed position one on top of the other without mutual interference between the necks of adjacent containers.

It will thus be apparent that our invention provides substantial improvements in molded plastic containers and in particular, in connection with containers for battery acid.

I claim:

A collapsible container comprising a stiff, flexible syn thetic plastic material defining an enclosure substantially rectangular in plan view and having rounded corners, said material providing top and bottom walls and back and side walls integral with one another, said top wall having an eccentric opening, an externally threaded upstanding tubular neck in said opening, said walls defining corrugations extending horizontally around the surface of the container, the corrugations comprising alternating ridges and valleys constituting a plurality of normally extended accordion pleats having fold lines coincidental with the ridges and valleys and extending parallel to one another horizontally around the surface of the container, said material having a thickness to normally enable self support of said container but permitting vertical collapse of said container under the action of a vertical compression force on the container, said top and bottom walls having rounded peripheral portions to strengthen the container to permit supporting a liquid contained in said container, said rounded peripheral portions of the top and bottom walls being provided with spaced narrow horizontal fold lines extending around each of said rounded corners thereof, the latter fold lines enabling collapse of the container under the action of a vertical compression force with the container unfilled while substantially unatfecting the increased strength provided by the rounded peripheral portions for supporting liquids in the container.

References Cited in the file of this patent UNITED STATES PATENTS 2,501,636 Smith Mar. 21, 1950 2,738,107 Graham Mar. 13, 1956 2,764,319 Weirncr Sept. 25, 1956 2,784,882 Du B018 Mar. 12, 1957 2,857,080 Elias Oct. 21, 1958 2,858,051 Cunningham Oct. 28, 1958 2,882,902 Juncher Apr. 21, 1959 2,893,611 Akers July 7, 1959 

